First of all apologise if this is in the wrong section, I wasn't sure where it should go.

I have 2 percentages and am finding the average of the 2 by multiplying them together like in the example below:

first percentage: 125%
second percentage: 75%

1.25 * 0.75 = 93.75%

My question is, is it possible to be able to give one percentage more of a weighting than the other number? So for example, I could say I trust the second figure more so give the second figure a certain amount more weighting in the calculation than the first number?

To find the average it's $\displaystyle \frac{a+b}{2}$ , which can be written as $\displaystyle \frac{a}{2} + \frac{b}{2}$

If you want to weight one more than the other, then change the fractions. For example, if you trusted a about twice as much as b, you could find it with $\displaystyle \frac{2}{3}a + \frac{b}{3}$
Just make sure that the fractions add up to 1.